Database | MySQL, MariaDB

This alert presents the status of the Galera node cluster component. If you receive this, it is an indication the cluster has been split into several components due to network failure.

What is Quorum

A majority (> 50%) of nodes. In the event of a network partition, only the cluster partition
that retains a quorum (if any) will remain Primary by default.1

What is a Primary Component?

In addition to single-node failures, the cluster may be split into several components due to
network failure. In such a situation, only one of the components can continue to modify the
database state to avoid history divergence. This component is called the Primary Component (PC).1

What is a Non-primary state Component?

The clusters without the quorum enter the non-primary state and begin attempt to connect with the
Primary Component.2

The codes of the Galera node cluster component status can be:
Code Description Alert Status
-1 Unknown. Critical
0 Primary Clear
1 Non-primary/quorum lost Critical
2 Disconnected Critical

For further information on Primary and non-Primary components please have a look at the
References and Sources section.

References and Sources
  1. Galera Cluster Glossary
  2. Galera Cluster Documentation